Welcome. I'm not a ham, nor an expert on Ubuntu, though I've making it work
and enjoying it for 5 years.

Just a couple of thoughts... Are you using something from the repositories
(via Synaptic, Muon Software Centre or similar)? Surprisingly, many Windows
programs will run, but not always perfectly, on Linux by using Wine or a
virtual machine.

Your best friend is the search engine and there aren't many problems that
you won't find an answer for there by intelligent Googling.

OKay, you are running Ubuntu,but what software are
you using to try & talk thru' the USB ports? I had no success
when trying to work PSK thru one of the earlier Ubuntu versions
and have not had time recently to try again.

Perhaps you could tell us what kind of usb devices and more about the
circumstances. Do they never work? Sometimes work? Is it limited to some
usb devices or all? Usually usb devices in Linux are mounted or
made available as needed. My scanner does not show until such time as I try
to use it. If I plug in a usb drive or one with a memory card such as my
e-reader then it will momentarily show in the notification area, but then
it tends to sit there until it is needed. Usb devices behave differently
depending on the device and the situation.

Ok, heres the poop. I haven't hooked up the printer yet...but i have a usb
soundcard the shows up and works fine (audio codecs), usb memory sticks work
fine. the interface I'm using is to transfer/ control transmitter info and sound
from digital transmitions to convert it to words on screen then transmit a
return reply the same way. The system shows the usb audio codecs and the usb
sticks when i plug them in, but DOES NOT show the interface when i plug it in
and i've looked and tried everything I can think of...so far. Got the feeling I
need to do some command prompt work, which will be a new ball game in
linux/ubuntu commands. been playing with dos commands since '83. Fldigi is a
ubuntu / linux program for multiple digital modes, there are 20 - 30 different
programs that do the same. I've never had any problems with this stuff in
windows. I'm sure it's just a matter of setting paramiters properly. Someone
mentioned adding user to the dailup group. But if the Rigexpert USB Tranceiver
Interface doesn't show up in the device manager window. Unless it is recognised,
how can it be accessed to try to make it work? I have 2 different rigexperts and
neither shows up. I need the rig (radio) control for frequency readout and
automatic information input to contact logs as well as radio control, and
digital signal translation.
Don't know what else to tell ya.
Hope this helps a little more.